Many large excavators are provided with bucket assemblies. The bucket assemblies can be used to remove earth, tar sand, etc. In a typical excavator, a lip is welded to an edge of a bucket body. The lip, viewed head-on or looking into the bucket, may be skewed rearwardly at its two opposite ends. Chisel-shaped excavating teeth are coupled to the lip and are used for digging. The lip can have a means for removably securing the teeth to the lip so that worn or damaged teeth can be replaced. Damaged or worn teeth should be replaced to avoid damage to the lip and the bucket body and to maintain the effectiveness of the bucket assembly.
Replacing damaged teeth is an expensive and time-consuming task. If the teeth become worn or damaged, workers must stop any excavation taking place to replace the worn or damaged teeth. Replacement teeth for excavators are relatively expensive parts that are made from relatively large quantities of hard materials such as carbon steel. The cost of the replacement teeth as well as the cost of the manpower used to replace worn or damaged teeth with replacement teeth inevitably results in increased project costs. In addition, replacing worn or damaged teeth frequently consumes the time of many workers and can result in project delays.
One factor which contributes to the increased frequency of damaged teeth is the lateral movement of the teeth during digging. During digging, the individual teeth can move from side-to-side. The lateral movement of the teeth causes them to repeatedly contact adjacent structures such as adjacent lip shrouds. This can result in increased wear on the teeth and increased stress. Consequently, frequent replacement of the teeth is needed in many instances.
Accordingly, it would be desirable to provide a lip assembly for an excavation bucket assembly which can reduce the frequency of replacing worn or damaged teeth. Embodiments of the invention are directed to this and other problems.
Embodiments of the invention are directed to lip assemblies, and in particular, lip assemblies for excavation bucket assemblies. In embodiments of the invention, tooth assemblies which are used in excavation bucket assemblies have restricted movement in a lateral direction. Contact between the tooth assemblies and other structures such as lip shrouds is reduced. This decreases the wear on the tooth assemblies and consequently increases their useful life. As a result, the frequency of replacing damaged or worn teeth is decreased in comparison to conventional excavation bucket assemblies.
One embodiment of the invention is directed to a lip assembly comprising a lip having an upper surface, a lower surface, a front portion, and a rear portion. A plurality of holes are disposed between the front portion and the rear portion, and each of the holes extends from the upper surface to the lower surface of the lip. The lip has a plurality of support members and each support member is disposed adjacent to a hole from the plurality of holes and inhibits the lateral movement of a tooth assembly coupled to the hole. The assembly also includes a plurality of tooth assemblies extending away from the lip. Each tooth assembly is respectively coupled to the lip via the plurality of holes.
Another embodiment of the invention is directed to a lip assembly comprising: (a) a U-shaped lip having (i) an upper surface, (ii) a lower surface, (iii) a front portion having projections and valleys, (iv) a rear portion, (v) a first plurality of holes disposed between the front portion and the rear portion and extending from the upper surface to the lower surface, (vi) a second plurality of holes disposed at the front portion, (vii) a plurality of ribs at the lower surface of the lip, wherein each hole of the first plurality of holes is disposed between a pair of ribs to inhibit the lateral movement of a tooth assembly disposed between the pair of ribs, and (viii) a plurality of lip shrouds respectively disposed on the projections of the front portion of the lip. The lip assembly also includes (b) a plurality of tooth assemblies extending away from the lip and respectively coupled to the lip via the first plurality of holes.
Another embodiment of the invention is directed to an excavation bucket assembly comprising: (a) an excavation bucket having a front portion, and (b) a lip assembly. The lip assembly comprises a lip having an upper surface, a lower surface, a front portion, and a rear portion. A plurality of holes is disposed between the front portion and the rear portion, and each of the holes extends from the upper surface to the lower surface of the lip. The lip has a plurality of support members and each support member is disposed adjacent to a hole from the plurality of holes and inhibits the lateral movement of a tooth assembly coupled to the hole. The lip assembly also includes a plurality of tooth assemblies extending away from the lip. Each tooth assembly is respectively coupled to the lip via the plurality of holes.
These and other embodiments are described in further detail below.